Improvement in ice-machines using ammonia



NITED STATES PATENT OFFICE.

ALEXANDER C. TWINING, OF NEW HAVEN, CONNECTICUT.

IMPROVEMENT IN ICE-MACHINES USING AMMONIA.

Specification forming part of Letters Patent No. 121,975, dated December 19, 1871; antedated December 9, 1871.

To all whom 'it may concern:

Beit known that I, ALEXANDER C. TWINTNG, of the city and county of New Haven and State of Connecticut, have invented a new and useful Improvement in the Ammonia Ice-Machine, commonly known as the Carre machine, and which is described7 in all the features and operations which concern my invention, in the patent granted by the United States to Mignon and Rouart on the 26th day of December, A. D. 1865; and I declare that the following is a full and complete description of my said invention, reference being had to the accompanying drawing.

My improvement consists of a mechanical or otherwise exhausting apparatus and other parts added to the ammonia or Carre machine, and which is used to `draw or receive into itself ammoniacal gas from the refrigerator, or from a separate reservoir of ammonia, erfrem other parts, as will befurther explained, and to throw or force it into the absorber with such increased pressure as may be necessary 5 or else it may be employed to take the like gas from the current of poor liquid77 on its way to the absorber, or, it might be, even from the boiler or retort itself under certain circumstances, and throw or force them into the liqueh'er 5 all for the purposes and in the manner which I come now to explain, and in certain other uses thereof.

In hot climates, and during the hot seasons especially, the natural waters employed, both for the cooling ofthe poor liquid preparatory to its entering the absorber, and of the rich liquid, which becomes heated by absorbing gas from the refrigerator-pipes, are too warm for the full performance to which the machine is otherwise com petent. The reason is that the affinity of the absorption water or poor liquid for ammoniaca] gas is much weakened by even a moderate increase of temperature-say 2()O to 300 Fahrenheit-so that, under that increase, the absorption liquor will not do full duty compared with that done by it in cooler months. lf pressure could be allowed" to rise higher in the absorber, the absorptive power might operate sufficiently; but this additional pressure would react in the refrigerator by diminishing in its pipes the excess of cold (so to term it) compared with the best temperature of the brine that surrounds the pipes in the freezing-vat; also the brine, becoming` raised in temperature, will freeze less rapidly the water in the molds. The best data now at command appear to show that an addition of but about au atmosphere is required in the absorber to counteract some 300 increase of temperature of the water in its cooling-coils. Accordingly, the first object of my plan herein set forth is to allow in the absorber the requisite augmentation of pressnre to keep up full absorption, but to prevent reaction in the refrigerator by interposing, as a cut-off, a mechanical means (or other means, in case a better can be found) for drawing out or taking up the gas from the refrigerator, and then compressing that gas to its higher density or tension in the absorber, into which the said interposed means or agency introduce it. The degree of compression required will ordinarily, at least, be so moderate, compared with the entire workin g-load of the machine, that the resulting economy over the necessary additional cost will be important.

For the mech anics convenience the accompanying drawing shows an outline of some principal parts of the Carre machine, designating them respectively by their familiar names, as the' retort or boiler, the liquetier, the absorber.,` the refrigerator, &c. These well-known parts can be rea-dily recognized in the drawing as well by their outlines and connections as by their names. It is only necessary to particularize in the description those parts that constitute vthe invention. Accordingly it is these alone that are drawrl shaded to make them the more easily recognized. The double-action pump P is the representative of the apparatus for taking in gas from the refrigerator, as before described, and compressing or forcing the same into the absorber. The inlet-pipes are m m, with valves (not shown) that may be of the ordinary sort. The outlet-pipe is n a. Of these the former is connected with and opens into the collecting-pipe at bottom of the refrigerator, or some other evaporating space of that vessel, or, better still, into the cold-vapor pipe that conducts the gas to the absorber. The latter or outlet-pipe opens into the absorber in any convenient part or manner. In the drawing both pipes enter the cold-vapor pipe e v at parts not far asunder, but capable of being isolated from each other by closing theintermediate cock y. This makes that pipe available in use for the pump but whenever it may be desired to put the latter out of action and operate in the old way you have only to open 3/ and close the cocks at m and n. The shaft which carries the crank which niay be.

alternates the pistons strokes in the pump may be susceptible of regulation in the frequency of its revolutions.- It may, for instance, be rotated by a conical drum fixed upon it and actuated by a band from ard-rum, to match, xed upon the main power-shaft of the machine. The object of such regulation would be to adapt the exhaust in amount to the varying exigencies of production, although, in case the performance is meant to be uniform in the evaporative element, no such regulation need be provided for after the best'capacities-of ypump and number of revolutions per minute shall have become understood. To be clear respecting the combination and working, observe that ever 1 part of the Carre apparatus employed will perform in its ordinary way, except that in c fu the cock y or its-equivalent intercepts the ammoniacal gas on its wayto the absorber and causes that gas to pass, through m m and its valves, into the expanding stroke or chamber of the pump, from which last the return of the piston expels it into the absorber through the outlet 'nu and the segment of o o, which forms a continuation ofthe latter. Of course, the pressure Which -is propagated from the retort into the absorber is that which rules also, essentially, throughout the compressing stroke (and chamber, for the -time being) of the pump 5 and, of course, also allthe net mechanical work is expended in that compression, of what degree soever or amount it The pump P (transfer-pump) might be employed in still another capacity. It will be seen that the pipe o o is so drawn as to show a continuation of the exhaust-pipe on into the retort, and also that the pipe p p shows a continuation of the exit or force pipe n into the liqueer. Accordingly, if you open the cocks, except m and n and the cocks s and c, (both hereafter to be explained,) the pump, when set to work, will draw ammoniacal gas out of the retort through o 0 and force it into the liquefier through p. This will reduce temperature in the retort as well as pressure, according to the degree of action or duty laid upon the pump. It will also perform a like reduction in the liqueiier if the hot gas, on its way to the latter, is made to pass through pipes surrounded by cooling water or some equivalent combinationrfor taking off excessive heat, thus leaving to the liquefier but little more than to dispose of the caloric of liquefaction. In fact,

Athis cooling-vessel and coil might be attached as an addition to the ammonia-machineindependently of the pump. rIhis sa-me system may be explained-by the drawingin still another way. Layying o o out of view, and supposingits office to be taken by the pipe e e, its inner siphon or bentarm turnin g upward into the gas instead of down ward into the liquor, andalso omitting or neglectin the exchanger, the drawing will show the hot-gas duct e c passing (as it then will be) directly into the cooler; thence, (neglecting w and the cocks,) along c b c o m, into l?, (when being in use,) and then through p into D, the liqueiier; or, if the cooler alone is employed without the pump, let c o m be continued into the liquefler by joining direct] y tothe pipe-p. It 'is one feature of this econom y that the' cooling waters, both of the absorber and the liqueer, are perfectly competent to be used over again for cooling this gas on account of the great excess of temperature inthe latter. Of course, it is understood that during the operation of this system the ordinary conduit between the retort and the liquefier will'be closed, say, by shutting the cock l), and also that the pump, or its action, must be contracted in dimensions or range according to the' greater density of the gas; but, although having thus described the foregoing gas-cooling system, and also the gastran sferrin g system from retort to liquefier by the pump or rotary or other equivalent, I do not claim them herein, either separately or in combin ation, but reserve them andthe following moditication of them for other patents which I find expedient to be applied for hereafter. And it is to be observed that this transfer action of the pump from retort to liqueer will involve but a comparatively moderate mechanical expenditure, both because it only works against a mere difference of pressures and because the piston or other working area will be small. Construction will be relatively cheapened whenever a single transfer-pump can supply different machines. For this it must draw out from alarge induction-pipe, common to all the retorts, and having adits to them, and a regulating-cock for each adit; and, also, it must compress into a common eductionpipe having adits and connections with all the liqueiiers, upon all analogous ideas to a like system, more fully described hereinafter, for another and independent combination.

Besides the mode, irst above described, of restoring or augmenting the action of affinity in the absorber there is asecond mode, entirely distinct therefrom and employing the transfer-pump in a distinct and new application. It consists in depriving the poor liquid, while 011 its way to the absorber, of a part of its contained ammonia by drawin g oi the latter by the pump or otherwise. This operation may be etfected at any part of the current desired, but most advantageously, it would seem, at some part which follows the cooling or cooler. By this deprivation of gas the poor liquid will come to the absorber both poorer and cooler. Every amount of gas thus abstracted and transferred into the liqueier will be so much added to the evaporative power in the refrigerator. This result is clear; but, in order to effect it, that portion of poor liquid which is immediately subject to the above-described exhaustion should, for the time, be isolated from all pressure, and only he open to the exhaust-that is to say, the aqua-ammonia must rest in its own receptacle, cut oii' from all actions other than the effect of the pump or its equivalent. These, th erefore, will be the essential parts in combination, to wit: The isolated receptacle and automatic cut-offs, and the pump or other exhauster.

Incidentally the appara-tus I now come to show will also serve perfectly as a regulator of the poor liquids current and as a conservator of that currents force or pressure propagated from the retort. For this last reason I call it herein the conservator. Its conservation will amount simply to a major fraction of the force necessary to work the ordinary ammonia or force pump. The conservator in the drawing is w. The poor-liquor pipe, leaving the cooler, enters, by the cock a, the head of the inverted pump w during the pistons ascent. The pressure of the current from the retort assists the ascent. The opposite cock b continues closed duringthe sa me ascent; but it opens just when the descent begins, and only closes at the end of that descent. This compels the poor liquor which had filled w below the pipe to pass up, by the pipe b, into the chamber above the piston. During this passage pressure is cut olf from beneath because the automatic cock a is closed, and also pressure is kept back from above by the self-actin g valve z. The poor liquid above the piston is therefore in circumstances to part with more or less of its gas to the exhaust of P, which takes eii'ect through the pipe c m and the open cock c; but so soon as the piston begins its ascent again b and o are reclosed and a and z are reopened, so that the liquoris forced onward anew through z to the absorber. To meet the above conditions it is assumed that the cocks a., b, and c are shackled together in one system of revolution imparted by the motive-power, either equably or at equably-recurring periods coincident as to frequency with the strokes of the piston in the conservator; also that their sheaths or beds open into the bore of w by a little less than half way round the circle of the beds, and with their plugs so disposed in the slots that each stands alternately shut off from and open into w for the time, each, of half a revolution. In the drawing the rod wis in place to connect the handle of c with similar and equal handle of a-not drawn, but assumed in analogy to that at lw, and thelike of a. and b in connection togetherso that, if one cock is' revolved, the movement is synchronous for the others. If the conservator is worked by both strokes of the double-action pump it should be geared to make two revolutions to one of I), and with the dead-points of both coincident; but if, by closing` the cocks 'i' and a, that exhaust is divided, as it obviously would be, between the conservator and the refrigerator, then the revolutions should be equal between the two. The chamber below the piston of l?, as seen in the drawing, would then receive the gas from the conservator through the pipe e lm, while, from the chamber above it, the same piston is forcing out the gas it has been receiving from the refrigerator through the compound pipe m 11,- but the return stroke of the under chamber forces the contents thereof into the liquefier.

Thus both these above-described operations may be worked in common by I?, or either be worked by itself alone; or else both may be kept up by a separate exhausting and compressing apparatus to each. But this operation for impoverishing the poor liquid would take the gas at a much less density from the conservator than the like is taken by the first-described plan from the refrigerator, and must reduce it to full density in the liquetier. Therefore,-although capable of invigorating absorption, as above set forth, yet its main value will probably be reserved for cases of exigency or special necessity; but the conservator, by itself and independently of P, has a regulating and power-saving capability.

The dimensions and revolutions of the transferpump between the refrigerator and the absorber are matters of calculation, in each separate case, by the mechanic. In a general way they may be determined on princi ples like the following: From the quantity of ice whic'h the machine can make by the hour you can deduce the weight of ammonia to be evaporated in the same time. It may approximate, ordinarily, to one-iifth the weight of the ice. Then from the known temperature and pressure in the refrigerator you deduce the volume of expansion for the gas evaporated This may come out, ordinarily, about eight hundred and thirty times the bulk of an equal weight of water. If the transferpump cannot be trusted for but a fractionsay three-fourths-of its theoretical duty, yoivould add correspondingly; or, for the fraction supposed, give to your exhausting and compressing apparatus a capacity to throw hourly at least eleven hundred times the bulk above specified. If several machines are working together it will be economy to lay the duty of several, or of all, upon a single central pump sufficient for all, and to connect them with it by a common exhaust or induction-pipe for the refrigerators and a compression or eduction-pipe, in like manner common to all, for the absorbers, respectively. Every refrigerator thus connected would open into the induction-pipe under control of a regulating-cock; and every absorber would be entered in like manner by a passage out from the eduction-pipe controlled by its own cock. A certain degree or range of variableness in the rapidity or period of the revolutions might prudently be provided` for in this case, in manner before mentioned, or by means already known. In the drawing this induction-pipe is lettered I. Its connection, into the exhaust of P is j'. Its connection with the refrigerator is through the com pound pipe kv and the controlling-cock k. On the other hand, the cduction-pipe is E, connected with the compression-chamber of P by the channel h, and with the absorber by l" and its controlling-cock. By either or all the above plans of procedure great steadiness ot production may be obtained through all seasons and years, provided the ammoniaca-l solution is kept up to a determinate and unvaried standard of richness; but, ordinarily, the aqua-ammonia degenerates in. strength one -week with another. To obviate this defect I propose, as a still further improvement, the combination of the ammonia-reservoir or retort C with the inductionpipe m m of the pump, extended for the purpose and capable of being stopped off by the cock S. It is true that aseparate pump might be appropriated to this use, which, after drawing gas through S and its pipe, should uforce it into the aforementioned eductiou-pipe to theabsorber or absorbers. This would be an exact equivalent for that purpose, and it would obviate all necessity of changing the amounts of action of the transfer-pump during the time of its use for this purpose; but such change would always be small in amount and brief' in duration, because the supply of gas from C would always be small `com- Otherwise be convenient.

pared with the entire evaporation, and because, also, the cock S would be closed as soon as the requisite supply was thrown in, and, in fact, by slightly-accelerating revolutions by the motivepower itself the pump would dispose of this additional gas and yet continue its full evaporatin g duty on the refrigerators. Therefore C may best be connected with P itself, (or with the common induction-pipe of the refrigerators, where such there is,) in accordance with the drawing. One facility additional is afforded by this last-explained improvement and use of P-that is, to graduate the richness of the solution or the aquaammonia-to a higher scale or range than would In fact, the vessel C may even be the retort in which the ammoniacal gas is evolved for use. I that case ms may be prolonged to unite with the retort at its own 1ccality, and ms may be laid under ground, if' desirable; or, otherwise, G may be the can or tank containing aqua-ammonia, to which some artificial heat should be applied to favor the escape of ammonia into the pump; but you may economize the evaporation from the aqua-ammonia as follows: Let cl d be a space surrounding1 C and forming, for the time being, a space of the poor-liquid channel e c, shown in the drawing as leading to an absorber, (presumably to that one nearest the transfer-pump, in case there are several absorbers fo a single pump.) This may be effected inexpensively by supplementary pipes furnished with restraining-cocks and projecting as mere branches from the poor-liquid pipe e c, to be coupled onto the inlet and outlet pipes, respectively, of cl d, as indicated in the drawing. The procedure will be this: O and d d will be filled with rich aqua-ammonia; then the connections e, e, will be made with the poor-liquid pipe by coupling on the branches, taking care, for the exclusion of air, to employ and close restrainingcocks immediately next the couplings. When d d is thus thrown into the circuit of poor liquor let the coupling of C to S in be made with the like precaution for the exclusion of air 5 then shut off' the lower exhaust-chamber and valve of the transfer-pump from the refrigerator by closingthe cocks r and u. By this one pair of the pistons strokes isi-appropriated to drawing ammonia from C, while the other pair-that operating through the pipes and valves above r and a-continues its duty of' evaporating from the refrigerators, and this to the sa-me amount as both pairs of strokes in ordinary circumstances, if you double the revolutions in frequency. Thus a partial vacuum will be formed in U, and the heat imparted by the poor liquor in d d will expel gas from the aqua-ammonia eifectually, while, at the same time, the poor liquor itself will be cooled, and will, for both reasons, operate the better in the absorber.

Still an improved and novel mode of' effecting this exhaustion of (l, and one applicable as well to certain other analogous purposes or operations, I will now describe in its outlines; but inasmuch as its details would complicate this specification, I omit to cla-im herein this improvement, which I come next to describe, and I reserve it, in its various applications for another patent, which I expect to apply for hereafter. The improved Inode referred to is the following: Let the cocks m and S be shackled together, or otherwise so coupled to the motive-power of the machine that either shall be shut when its fellow is open, and, automatically, let the coupling shut m (and so cut off the refrigerator) and at the same time open S just before the piston has completed its stroke either way; but at any required point or period in the early part of the succeeding or opposite stroke-say one-eighth the full strokelet the above-mentioned position of the two cocks last mentioned be suddenly reversed, so that during the remaining partsay seven-eighths of the full stroke-m m Will be open to the refrigerator but closed to the ammonia-tank or can. By this ar Mangement, it is obvious, any desired fractional part of either stroke, (or of both,) and, consequently, the same ofthe entire exhaustion of P, may be utilized to take in ammonia from C, and all the rest to take in gas from the refrigerator. Of' course you may so proportion this fraction of the entire work as to be ofasmall relative amount for a continued period; or you may accelerate the pumps actions or strokes a little in frequency.

The aq 11a-ammonia of the can C, spoken of above, may be the weak liquor ofthe gas-works after the same is cleared sufficiently of its impurities by settling and otherwise. Conveniently to employ this let the pipe fu o, after passing down the absorber, turn out of 'it near the bottom through the two-way cock A and be continued on by a smaller pipe, A c, which can be coupled to the inlet c, e, ofthe space d d. In its ordinary position the cock A affords an open way, of o o, into the absorber, and at the same time closes A e, to C 5 but, reversing this position, you may close o o to the absorber and open it to G, or, rather, to d d,- then, having U, the can, suiciently capacious and full of' the above-mentioned weak liquor, and d d also supplied with pure water, and the couplings and cocks properly made and adjusted, you set the pump at work. It will draw ammonia out of C through S by the exhaust, and then, by the com pressin g-stroke, force it through n V A e, into d cl, Where it will be taken into solution by the pure water. When the Weak liquor in C is exhausted another charge may be let in. The heat of absorption in d d will enable the ammonia to evaporate from C (or additional heat may be employed) until the aqua-ammonia in d d. shall be of full strength. Then the coupling of e, e, to A c, may be changed to that above described With the poor-liquor pipe, (and the saine of d e,) and so d d be made a space of that poor-liquor channel into w hich the newly-produced aqua-ammonia is taken and adopted into the working of the machine. For clearness, observe that if u i; (and also P) is used bodily for the last-descr bed purpose, that use supposes a suspension, for the time, of their ordinary use in the machine; but all such suspension may be avoided by a simple equivalent construction-t1 e., let the inlet-pipe d d, that is, e, e, be continued up and coupled to a a, and let the cocks n and e, be so shackled together or coupled to the motive-power that, automatically, u shall be open When e, is closed, and

vice versa, and also a be closed for simply such part or fraction as may be desired of either or both compressingstrokes of the exhausting and com pressing apparatus, this system being the counterpart of the like applied to the exhaust-pipe and chamber or stroke, as above mentioned, and in like manner With that hereby reserved for another patent to be applied for. But if, as may be done, another and separate exhausting and compressing` apparatus is employed, with simply such parts ofthe above in combination as are needful to theuseful effect, it Will constitute an equivalent combination or system that may be employed ,either at the ice-Works or the gas-Works, at pleasure. If the rst product is not complete it may be used over again as the mother-liquorin G, and so on.

It is obvious that the transfer-pump, if connected by the induction-pipe and its appurtenances above described to dilierent refrigerators, may be employed to throw their several contents together into a single absorber made of a capacity to serve them all in union or that, by means of an eduction-pipe and appurtenances above described, the contents of a single large refrigerator A may be distributed among several absorbers; also,

that a rota-ry pump should be employed, if practicable,merging the alternate exhaust-strokes in one equable exhaust, on the one part, and the compressing-strokes into a continuous compressing action on the other.

A due reference and regard being had to the reserved claims hereinbefore specitied, respectively, What l now claim, and desire to secure by Letters Patent, is the following:

l. The combination of the tran sfer-pump or any equivalent apparatus with the absorber and the refrigerator of an ammonia ice-machine, or the description of machine referred to herein, to cut oft` pressure or tension of gasin the absorberfrom the refrigerator and transfer the amlnoniacal gas, with such tension, from the refrigerator to the absorber, in manner and use substantially as described.

2. In the same or like machine, the combination of an induction-pipe common to different refrigerators With the transfer-pump orany equivaient thereof and an absorber or absorbers, substantially as and for the purpose described; and, in like manner and form, the combination of an eduction-pipe common to different absorbers with the transfer-pump and with a refrigerator or refrigerators.

3. The combination of the essential parts, or of any substantially the same., in the above-described apparatus or process for transferring ammonia from the poor-liquor channel or conduit to the liquefier; also, the conservator, Whether used as part of said combination or employed by itself, to conserve the power or regulate the current of the poor liquid, as described.

4. The use, in combination, `of the essential parts, or any competent number of them, or of any substantially the same,in the above-described apparatus or process for supplying a-mmoniacal gas to the machines, and also in the above-described apparatus for procuring or producing pure or concentrated aqua-ammonia from impure or Weak liquor.

ALEXR. C. TWINING.

Witnesses WM. GRANT, 

